1. Field of the Invention
The invention relates to a digital camera, a digital camera control apparatus, a digital camera system, a digital camera control method, and a medium which can be controlled by a communication.
2. Related Background Art
Hitherto, there has been proposed a digital camera system such that an image photographed by a digital camera is displayed or the like on a personal computer (hereinafter, simply referred to as a PC) or, contrarily, data managed on the PC is recorded to the digital camera.
FIG. 4 is a constructional diagram showing an outline of a digital camera system. In FIG. 4, reference numeral 1003 denotes a PC and 1007 indicates a digital camera. The digital camera 1007 has a PCMCIA card slot 1008 and can record images in a PCMCIA card (not shown).
Reference numeral 1006 denotes a cable to connect the PC 1003 and the digital camera 1007. A serial or parallel cable is used as a cable 1006. The PC 1003 performs a communication through the cable 1006 and can read the images recorded in the PCMCIA card of the digital camera 1007 or can write data into the PCMCIA card.
FIG. 5 is a block diagram showing a constructional example of the conventional digital camera 1007. In FIG. 5, reference numeral 1107 denotes hardware of the digital camera 1007 and 1100 indicates software. Only main portions of the digital camera 1007 are shown in FIG. 5.
In FIG. 5, reference numeral 1106 denotes an image pickup device comprising a CCD or the like which is necessary for image pickup. Reference numeral 1105 denotes a recording medium such as a PCMCIA card or the like to store the photographed image data or the like. Reference numeral 1104 denotes a file system having a function for enabling another software to perform an input/output process of the file without being aware of the hardware.
Reference numeral 1103 denotes a photographing information management unit having a function to manage various information which are necessary to perform a photographing. As information to be managed, there are the number of images which can be photographed and stored in the recording medium 1105, the number that is used as a name of image to be photographed at the next time, and the like.
Reference numeral 1101 denotes a photographing execution unit which functions such that the image pickup device 1106 is driven and photographing is performed, where the photographed images are recorded with names using serial numbers through the photographing information management unit 1103, and if the number of images which can be photographed and stored in the recording medium 1105 is insufficient, a decision is made so as not to perform the photographing operation or the like.
Reference numeral 1108 denotes a communication port. When communicating with the PC 1003 as shown in FIG. 4, the serial or parallel cable 1006 is connected to the communication port 1108. Reference numeral 1102 denotes a communication control unit which functions such that a signal transmitted from the communication port 1108 is processed, and in accordance with a request from the PC 1003, the photographed image is read through the file system 1104 and is transmitted, or unnecessary images are deleted, or data sent from the PC 1003 is written.
In the conventional digital camera system constructed as mentioned above, the PC 1003 can directly access the file system 1104 of the digital camera 1007 by communication via the cable 1006. For example, the images photographed by the digital camera 1007 can be deleted or a file other than the images can be written.
Therefore, in the case where a user intends to perform a photographing operation using the digital camera 1007 after an operation such as deleting photographed images or writing a file other than the images which has been executed by the PC 1003, there is a possibility that a contradiction may occur with the information which the photographing information management unit 1103 contains.
For example, it is assumed that when the images to which the names from No. 1 to No. 5 were allocated have been photographed and stored in the recording medium 1105, the photographing information management unit 1103 prepares No. 6 as a number that is used as a name of an image to be photographed at the next time.
In this instance, a case where the PC 1003 directly accesses the file system 1104 and deletes the image of No. 5 and, thereafter, performs a photographing operation is now considered. In this case, although it is inherently sufficient to photograph the image by the name of No. 5, since the photographing information management unit 1103 does not have means for detecting that the image of No. 5 was deleted, there is a problem such that the number that is used as a name of the image to be subsequently photographed cannot be changed and an image having the name of No. 6 is photographed.
Or, in the case where the digital camera 1007 intends to perform a photographing operation after the PC 1003 has written a file other than images into the recording medium 1105, in spite of a fact that a vacant capacity of the recording medium 1105 has been reduced, the photographing information management unit 1103 cannot detect it. There is, consequently, a fear that although the remaining unused capacity of the recording medium 1105 is actually insufficient, the photographing execution unit 1101 may execute a photographing operation.
In consideration of the above drawbacks, it is an object of the invention to enable storage means to be preferably managed.
Another object of the invention is to enable storage means of a digital camera to be preferably managed.
Still another object of the invention is to make it possible to manage storage means of a digital camera which is connected to a host computer.
A further object of the invention is to make it possible to normally perform photographing and recording operations using a digital camera even after a file system in the digital camera has been changed using an external apparatus such as a computer or the like.
To accomplish the above objects, according to a preferred embodiment of the invention, there is provided a digital camera comprising: recording means which can be rewritten from the outside; and information holding means for holding information regarding the recording means, wherein the information holding means updates the information regarding the recording means while reflecting the contents in the recording means.
In a system comprising a host computer and a digital camera, it is a further object of the present invention to provide a digital camera and host computer which make it possible to preferably manage storage means and to also provide a control method for controlling these apparatuses and a medium in which such a control method has been stored.
The above and other objects and features of the present invention will become apparent from the following detailed description and the appended claims with reference to the accompanying drawings.